Method for Producing Carboxamides

ABSTRACT

The present invention relates to a novel process for preparing known fungicidally active 1,3-dimethyl-5-fluoro- 1 H-pyrazole-4-carboxamides from the corresponding acid fluoride and aniline derivatives in the presence of alkylpyridine derivatives as an acid acceptor.

The present invention relates to a novel process for preparing known fungicidally active 1,3-dimethyl-5-fluoro-4-carboxamides from the corresponding acid fluoride and aniline derivatives in the presence of alkylpyridine derivatives as an acid acceptor.

It is already known that 1,3-dimethyl-5-fluoro-1H-pyrazole-4-carboxamides are obtained by reacting the corresponding acid fluoride with the desired aniline derivative (cf. EP-A 0 776 889). According to this description, preference is given to using bicyclic tertiary amines such as diazabicyclooctane (DABCO), diazabicyclononene (DBN) or diazabicycloundecene (DBU) as the acid acceptor. The reaction with DABCO only affords a yield of 80%. Moreover, DABCO is unsuitable for industrial scale reactions, since this reagent is very expensive and cannot be recycled.

It has now been found that carboxamides of the formula (I)

in which

-   R is C₃-C₁₂-cycloalkyl, C₃-C₁₂-cycloalkenyl, C₆-C₁₂-bicycloalkyl,     C₂-C₁₂-oxacycloalkyl, C₄-C₁₂-oxacycloalkenyl, C₃-C₁₂-thiacycloalkyl,     C₄-C₁₂-thiacycloalkenyl, C₂-C₁₂-azacycloalkyl, each of which may     optionally be mono- or polysubstituted identically or differently by     C₁-C₈-alkyl, C₁-C₈-alkoxy, halogen and/or cyano, or phenyl which is     optionally mono- to pentasubstituted identically or differently,     where the substituents are each selected from the list W¹,     -   or unsubstituted C₂-C₂₀-alkyl,     -   or C₁-C₂₀-alkyl which is mono- or polysubstituted identically or         differently by halogen, C₁-C₆-alkylthio, C₁-C₆-alkylsulfinyl,         C₁-C₆-alkylsulfonyl, C₁-C₆-alkoxy, C₁-C₆-alkylamino,         di(C₁-C₆-alkyl)amino, C₁-C₆-haloalkylthio,         C₁-C₆-haloalkylsulfinyl, C₁-C₆-haloalkylsulfonyl,         C₁-C₆-haloalkoxy, C₁-C₆-haloalkylamino,         halo-di(C₁-C₆-alkyl)amino, —SiR¹R²R³ and/or C₃-C₆-cycloalkyl,         where the cycloalkyl moiety may in turn optionally be mono- to         tetrasubstituted identically or differently by halogen,         C₁-C₂₀-alkyl and/or C₁-C₄-haloalkyl, -   W¹ is halogen, cyano, nitro, amino, hydroxyl, C₁-C₈-alkyl,     C₁-C₈-alkoxy, C₁-C₈-alkylthio, C₁-C₈-alkylsulfinyl,     C₁-C₈-alkylsulfonyl, C₂-C₆-alkenyl, C₂-C₆-alkenyloxy;     C₁-C₆-haloalkyl, C₁-C₆-haloalkoxy, C₁-C₆-haloalkylthio,     C₁-C₆-haloalkylsulfinyl or C₁-C₆-haloalkylsulfonyl having in each     case from 1 to 13 identical or different halogen atoms;     C₂-C₆-haloalkenyl or C₂-C₆-haloalkenyloxy having in each case from 1     to 11 identical or different halogen atoms; C₃-C₆-cycloalkyl or     C₃-C₆-cycloalkyloxy; -   R¹ and R² are each independently hydrogen, C₁-C₈-alkyl,     C₁-C₈-alkoxy, C₁-C₄-alkoxy-C₁-C₄-alkyl, C₁-C₄-alkylthio-C₁-C₄-alkyl     or C₁-C₆-haloalkyl, -   R³ is hydrogen, C₁-C₈-alkyl, C₁-C₈-alkoxy, C₁-C₄-alkoxy-C₁-C₄-alkyl,     C₁-C₄-alkylthio-C₁-C₄-alkyl, C₂-C₈-alkenyl, C₂-C₈-alkynyl,     C₁-C₆-haloalkyl, C₂-C₆-haloalkenyl, C₂-C₆-haloalkynyl,     C₃-C₆-cycloalkyl, or in each case optionally substituted phenol or     phenylalkyl,     are obtained in a simple manner by     reacting 5-fluoro-1,3-dimethyl-1H-pyrazole-4-carbonyl fluoride of     the formula (II)

with aniline derivatives of the formula (III)

in which R is as defined above, in the presence of an acid acceptor of the formula (IV)

in which R⁴ and R⁵ are each independently hydrogen or C₁-C₃-alkyl.

It is surprisingly possible to prepare the carboxamides of the formula (I) under the inventive conditions in high purity and selectivity with good yields through the selection of the acid acceptor of the formula (IV). A further advantage of the process according to the invention is that the acid acceptor of the formula (IV) used can be recovered completely.

When, for example, 5-fluoro-1,3-dimethyl-1H-pyrazole-4-carbonyl fluoride and 2-(1,3-dimethylbutyl)phenylamine are used as starting materials, and 2,6-dimethylpyridine is used as the acid acceptor, the process according to the invention can be illustrated by the following scheme:

The 5-fluoro-1,3-dimethyl-1H-pyrazole-4-carbonyl fluoride of the formula (II) used as a starting material in the performance of the process according to the invention is known (cf. EP-A 0 776 889).

The aniline derivatives also used as starting materials in the performance of the process according to the invention are defined in general terms by the formula (III).

-   R is preferably C₃-C₈-cycloalkyl, C₃-C₈-cycloalkenyl,     C₆-C₁₀-bicycloalkyl, C₂-C₇-oxacycloalkyl, C₄-C₇-oxacycloalkenyl,     C₃-C₇-thiacycloalkyl, C₄-C₇-thiacycloalkenyl, C₂-C₇-azacycloalkyl,     each of which may optionally be mono- to tetrasubstituted     identically or differently by C₁-C₄-alkyl, C₁-C₄-alkoxy, fluorine,     chlorine, bromine and/or cyano,     -   or phenyl which is mono- to trisubstituted identically or         differently, where the substituents are selected from the list         W¹,     -   or unsubstituted C₂-C₁₂-alkyl (such as ethyl and straight-chain         or branched propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,         decyl, undecyl and dodecyl)     -   or C₁-C₁₂-alkyl (such as methyl, ethyl and straight-chain or         branched propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,         decyl, undecyl and dodecyl) which is mono- or polysubstituted         identically or differently by fluorine, chlorine, bromine,         iodine, C₁-C₆-alkylthio, C₁-C₄-alkylsulfinyl,         C₁-C₄-alkylsulfonyl, C₁-C₄-alkoxy, C₁-C₄-alkylamino,         di(C₁-C₄-alkyl)amino, C₁-C₄-haloalkylthio,         C₁-C₄-haloalkylsulfinyl, C₁-C₄-haloalkylsulfonyl,         C₁-C₄-haloalkoxy, C₁-C₄-haloalkylamino,         halo-di(C₁-C₄-alkyl)amino having in each case from 1 to 9         fluorine, chlorine and/or bromine atoms, —SiR¹R²R³, cyclopropyl,         dichlorocyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl. -   R is more preferably cyclopentyl, cyclohexyl, cycloheptyl,     bicyclo[2.2.1]heptyl, or phenyl monosubstituted in the 4 position,     phenyl disubstituted identically or differently in the 3,4, 2,3, 2,     4 or 3,5 position, or phenyl trisubstituted identically or     differently in the 2,4,6 position, where the substituents are each     selected from the list W¹,     -   or unsubstituted C₃-C₁₀-alkyl (such as propyl, 1-methylethyl,         butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl,         n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,         1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl,         1-ethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl,         3-methylpentyl, 4-methylpentyl, 1,2-dimethylbutyl,         1,3-dimethylbutyl, 2,3-dimethylbutyl, 1,1-dimethylbutyl,         2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl,         1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl,         1-ethyl-3-methylpropyl, n-heptyl, 1-methylhexyl, 1-ethylpentyl,         2-ethylpentyl, 1-propylbutyl, octyl, 1-methylheptyl,         2-methylheptyl, 1-ethylhexyl, 2-ethylhexyl, 1-propylpentyl,         2-propylpentyl, nonyl, 1-methyloctyl, 2-methyloctyl,         1-ethylheptyl, 2-ethylheptyl, 1-propylhexyl, 2-propylhexyl,         decyl, 1-methylnonyl, 2-methylnonyl, 1-ethyloctyl, 2-ethyloctyl,         1-propylheptyl and 2-propylheptyl)     -   or C₁-C₁₀-alkyl (such as methyl, ethyl, propyl, 1-methylethyl,         butyl, 1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl,         n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl,         1,2-dimethylpropyl, 1,1-dimethylpropyl, 2,2-dimethylpropyl,         1-ethylpropyl, n-hexyl, 1-methylpentyl, 2-methylpentyl,         3-methylpentyl, 4-methylpentyl, 1,2-dimethylbutyl,         1,3-dimethylbutyl, 2,3-dimethylbutyl, 1,1-dimethylbutyl,         2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl,         1,2,2-trimethylpropyl, 1-ethylbutyl, 2-ethylbutyl,         1-ethyl-3-methylpropyl, n-heptyl, 1-methylhexyl, 1-ethylpentyl,         2-ethylpentyl, 1-propylbutyl, octyl, 1-methylheptyl,         2-methylheptyl, 1-ethylhexyl, 2-ethylhexyl, 1-propylpentyl,         2-propylpentyl, nonyl, 1-methyloctyl, 2-methyloctyl,         1-ethylheptyl, 2-ethylheptyl, 1-propylhexyl, 2-propylhexyl,         decyl, 1-methylnonyl, 2-methylnonyl, 1-ethyloctyl, 2-ethyloctyl,         1-propylheptyl and 2-propylheptyl) which is mono- or         polysubstituted identically or differently by fluorine,         chlorine, methylthio, ethylthio, n- or isopropylthio, n-, iso-,         sec-, tert-butylthio, pentylthio, hexylthio, methylsulfonyl,         ethylsulfonyl, n- or isopropylsulfonyl, n-, iso-, sec-,         tert-butylsulfonyl, methoxy, ethoxy, n- or isopropoxy, n-, iso-,         sec-, tert-butoxy, methylamino, ethylamino, n- or         isopropylamino, n-, iso-, sec-, tert-butylamino, dimethylamino,         diisopropylamino, trifluoromethylthio, trifluoromethoxy,         —SiR¹R²R³, cyclopropyl, dichlorocyclopropyl, cyclobutyl,         cyclopentyl or cyclohexyl. -   W¹ is preferably fluorine, chlorine, bromine, methyl, ethyl, n- or     i-propyl, n-, i-, s- or t-butyl, methoxy, ethoxy, n- or i-propoxy,     trifluoromethyl, trifluoroethyl, difluoromethoxy, trifluoromethoxy,     difluorochloromethoxy, trifluoroethoxy. -   W¹ is more preferably fluorine, chlorine or bromine. -   R¹ and R² are each independently preferably C₁-C₆-alkyl,     C₁-C₆-alkoxy, C₁-C₃-alkoxy-C₁-C₃-alkyl or     C₁-C₃-alkylthio-C₁-C₃-alkyl. -   R¹ and R² are each independently more preferably methyl, ethyl,     methoxy, ethoxy, methoxymethyl, ethoxymethyl, methoxyethyl,     ethoxyethyl, methylthiomethyl, ethylthiomethyl, methylthioethyl or     ethylthioethyl. -   R¹ and R² are each independently most preferably methyl, methoxy,     methoxymethyl or methylthiomethyl. -   R¹ and R² are especially preferably each methyl. -   R³ is preferably C₁-C₆-alkyl, C₁-C₆-alkoxy,     C₁-C₃-alkoxy-C₁-C₃-alkyl, C₁-C₃-alkylthio-C₁-C₃-alkyl,     C₃-C₆-cycloalkyl, phenyl or benzyl. -   R³ is more preferably methyl, ethyl, n- or isopropyl, n-, sec-, iso-     or tert-butyl, methoxy, ethoxy, n- or isopropoxy, n-, sec-, iso- or     tert-butoxy, methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl,     methylthiomethyl, ethylthiomethyl, methylthioethyl, ethylthioethyl,     cyclopropyl, phenyl or benzyl. -   R³ is most preferably methyl, ethyl, n- or isopropyl, iso- or     tert-butyl, methoxy, isopropoxy, iso- or tert-butoxy. -   R³ is especially preferably methyl.

Preference is given to using aniline derivatives of the formula (III-1)

in which R is as defined above in the process according to the invention.

Preference is also given to using aniline derivatives of the formula (III-2)

in which R is as defined above in the process according to the invention.

Preference is also given to using aniline derivatives of the formula (III-3)

in which R is as defined above in the process according to the invention.

Particular preference is given to using aniline derivatives of the formula (III-1).

Aniline derivatives of the formula (III) or (III-1), (III-2) and (III-3) are known or can be prepared in a known manner (cf. EP-A 0 776 889, WO 03/010149).

The acid acceptors used in the performance of the process according to the invention are defined in general terms by the formula (IV). In this formula (IV), R⁴ and R⁵ are preferably each independently methyl or ethyl. Particular preference is given to the following acid acceptors of the formula (IV): 2-methylpyridine, 2,3-dimethylpyridine, 2-methyl-5-ethylpyridine, 2,6-dimethylpyridine, 2,4-dimethylpyridine, 3,4-dimethylpyridine, 2,4,6-trimethylpyridine.

Acid acceptors of the formula (IV) are known synthesis chemicals.

The process according to the invention can be performed in the presence of a diluent. Useful diluents for this purpose are all inert organic solvents, preferably aliphatic, alicyclic or aromatic hydrocarbons, for example petroleum ether, hexane, heptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene or decalin; halogenated hydrocarbons, for example chlorobenzene, dichlorobenzene, dichloromethane, chloroform, tetrachloromethane, dichloroethane or trichloroethane; ethers such as diethyl ether, diisopropyl ether, methyl t-butyl ether, methyl t-amyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, 1,2-diethoxyethane or anisole; ketones such as acetone, butanone, methyl isobutyl ketone or cyclohexanone; nitriles such as acetonitrile, propionitrile, n- or i-butyronitrile or benzonitrile; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformanilide, N-methylpyrrolidone or hexamethylphosphoramide, more preferably chlorobenzene or toluene.

In the performance of the process according to the invention, the reaction temperatures can be varied within a wide range. In general, temperatures of 100° C. to 150° C., preferably temperatures of 120° C. to 145° C., are employed.

In the performance of the process according to the invention, generally between 0.8 and 1.5 mol, preferably equimolar amounts, of aniline derivatives of the formula (III) and between 0.8 and 1.5 mol, preferably equimolar amounts, of an acid acceptor of the formula (IV) are used per mole of the 5-fluoro-1,3-dimethyl-1H-pyrazole-4-carbonyl fluoride of the formula (II).

Depending on the reactivity of the reactants, the reaction time may be up to 30 hours, but the reaction can also be terminated earlier in the case of complete conversion. Preference is given to reaction times of from 10 to 20 hours.

All processes according to the invention are generally performed under standard pressure. However, it is also possible to work under elevated or reduced pressure—generally between 0.1 bar and 10 bar.

The carboxamides of the formula (I) preparable by the process according to the invention are valuable fungicides (cf., for example, WO 03/010149).

The inventive preparation of carboxamides of the formula (I) is described in the examples which follow, which further illustrate the above description. However, the examples should not be interpreted in a restrictive manner.

PREPARATION EXAMPLES

Under protective gas (argon), a solution of 11.25 g (105 mmol) of 2,6-dimethylpyridine and 18.05 g (100 mmol) of 2-(1,3-dimethylbutyl)phenylamine in 40 ml of chlorobenzene is initially charged. 16.17 g (100 mmol) of 5-fluoro-1,3-dimethyl-1H-pyrazole-4-carbonyl fluoride are added and the mixture is stirred under reflux for 21 h. For workup, the mixture is allowed to cool, stirred with 100 ml of 1 N hydrochloric acid and extracted three times with 100 ml each time of ethyl acetate. The combined organic phases are washed once with 100 ml of water, dried over magnesium sulfate and concentrated under reduced pressure. The resulting suspension is stirred with 50 ml of hexane at room temperature for 2 h. This affords 28.25 g (88% of theory) of N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethyl-1H-pyrazole-4-carboxamide in the form of crystals (melting point 104-106° C.). 

1. A process for preparing a carboxamide of formula (I)

in which R is C₃-C₁₂-cycloalkyl, C₃-C₁₂-cycloalkenyl, C₆-C₁₂-bicycloalkyl, C₂-C₁₂-oxacycloalkyl, C₄-C₁₂-oxacycloalkenyl, C₃-C₁₂-thiacycloalkyl, C₄-C₁₂-thiacycloalkenyl, C₂-C₁₂-azacycloalkyl, each of which may optionally be mono- or polysubstituted identically or differently by C₁-C₈-alkyl, C₁-C₈-alkoxy, halogen and/or cyano, or phenyl which is optionally mono- to pentasubstituted identically or differently, where the substituents are each selected from the list W¹, or unsubstituted C₂-C₂₀-alkyl, or C₁-C₂₀-alkyl which is mono- or polysubstituted identically or differently by halogen, C₁-C₆-alkylthio, C₁-C₆-alkylsulfinyl, C₁-C₆-alkylsulfonyl, C₁-C₆-alkoxy, C₁-C₆-alkylamino, di(C₁-C₆-alkyl)amino, C₁-C₆-haloalkylthio, C₁-C₆-haloalkylsulfinyl, C₁-C₆-haloalkylsulfonyl, C₁-C₆-haloalkoxy, C₁-C₆-haloalkylamino, halo-di(C₁-C₆-alkyl)amino, —SiR¹R²R³ and/or C₃-C₆-cycloalkyl, where the cycloalkyl moiety may in turn optionally be mono- to tetrasubstituted identically or differently by halogen, C₁-C₂₀-alkyl and/or C₁-C₄-haloalkyl, W¹ is halogen, cyano, nitro, amino, hydroxyl, C₁-C₈-alkyl, C₁-C₈-alkoxy, C₁-C₈-alkylthio, C₁-C₈-alkylsulfinyl, C₁-C₈-alkylsulfonyl, C₂-C₆-alkenyl, C₂-C₆-alkenyloxy; C₁-C₆-haloalkyl, C₁-C₆-haloalkoxy, C₁-C₆-haloalkylthio, C₁-C₆-haloalkylsulfinyl or C₁-C₆-haloalkylsulfonyl having in each case from 1 to 13 identical or different halogen atoms; C₂-C₆-haloalkenyl or C₂-C₆-haloalkenyloxy having in each case from 1 to 11 identical or different halogen atoms; C₃-C₆-cycloalkyl or C₃-C₆-cycloalkyloxy; R¹ and R² are each independently hydrogen, C₁-C₈-alkyl, C₁-C₈-alkoxy, C₁-C₄-alkoxy-C₁-C₄-alkyl, C₁-C₄-alkylthio-C₁-C₄-alkyl or C₁-C₆-haloalkyl, R³ is hydrogen, C₁-C₈-alkyl, C₁-C₈-alkoxy, C₁-C₄-alkoxy-C₁-C₄-alkyl, C₁-C₄-alkylthio-C₁-C₄-alkyl, C₂-C₈-alkenyl, C₂-C₈-alkynyl, C₁-C₆-haloalkyl, C₂-C₆-haloalkenyl, C₂-C₆-haloalkynyl, C₃-C₆-cycloalkyl, or in each case optionally substituted phenol or phenylalkyl, said process comprising reacting 5-fluoro-1,3-dimethyl-1H-pyrazole-4-carbonyl fluoride of formula (II)

with aniline derivatives of formula (III)

in which R is as defined above, in the presence of an acid acceptor of formula (IV)

in which R⁴ and R⁵ are each independently C₁-C₃-alkyl.
 2. The process as claimed in claim 1, wherein the acid acceptor used is 2-methylpyridine, 2,3-dimethylpyridine, 2-methyl-5-ethylpyridine, 2,6-dimethylpyridine, 2,4-dimethylpyridine, 3,4-dimethylpyridine, and/or 2,4,6-trimethylpyridine.
 3. The process as claimed in claim 1, wherein a temperatures of from 100 to 150° C. is employed.
 4. The process as claimed in claim 1, wherein an aniline derivative of formula (III-1)

is used.
 5. The process as claimed in claim 1, wherein 2-(1,3-dimethylbutyl)-phenylamine is used as the aniline derivative of the formula (III).
 6. The process as claimed in claim 2, wherein a temperature of from 100 to 150° C. is employed.
 7. The process as claimed in claim 2, wherein an aniline derivative of formula (III-1)

is used.
 8. The process as claimed in claim 3, wherein an aniline derivative of formula (III-1)

is used.
 9. The process as claimed in claim 2, wherein 2-(1,3-dimethylbutyl)-phenylamine is used as the aniline derivative of the formula (III).
 10. The process as claimed in claim 3, wherein 2-(1,3-dimethylbutyl)-phenylamine is used as the aniline derivative of the formula (III).
 11. The process as claimed in claim 4, wherein 2-(1,3-dimethylbutyl)-phenylamine is used as the aniline derivative of the formula (III).
 12. A carboxamide of formula I

in which R is C₃-C₁₂-cycloalkyl, C₃-C₁₂-cycloalkenyl, C₆-C₁₂-bicycloalkyl, C₂-C₁₂-oxacycloalkyl, C₄-C₁₂-oxacycloalkenyl, C₃-C₁₂-thiacycloalkyl, C₄-C₁₂-thiacycloalkenyl, C₂-C₁₂-azacycloalkyl, each of which may optionally be mono- or polysubstituted identically or differently by C₁-C₈-alkyl, C₁-C₈-alkoxy, halogen and/or cyano, or phenyl which is optionally mono- to pentasubstituted identically or differently, where the substituents are each selected from the list W¹, or unsubstituted C₂-C₂₀-alkyl, or C₁-C₂₀-alkyl which is mono- or polysubstituted identically or differently by halogen, C₁-C₆-alkylthio, C₁-C₆-alkylsulfinyl, C₁-C₆-alkylsulfonyl, C₁-C₆-alkoxy, C₁-C₆-alkylamino, di(C₁-C₆-alkyl)amino, C₁-C₆-haloalkylthio, C₁-C₆-haloalkylsulfinyl, C₁-C₆-haloalkylsulfonyl, C₁-C₆-haloalkoxy, C₁-C₆-haloalkylamino, halo-di(C₁-C₆-alkyl)amino, —SiR¹R²R³ and/or C₃-C₆-cycloalkyl, where the cycloalkyl moiety may in turn optionally be mono- to tetrasubstituted identically or differently by halogen, C₁-C₂₀-alkyl and/or C₁-C₄-haloalkyl, W¹ is halogen, cyano, nitro, amino, hydroxyl, C₁-C₈-alkyl, C₁-C₈-alkoxy, C₁-C₈-alkylthio, C₁-C₈-alkylsulfinyl, C₁-C₈-alkylsulfonyl, C₂-C₆-alkenyl, C₂-C₆-alkenyloxy; C₁-C₆-haloalkyl, C₁-C₆-haloalkoxy, C₁-C₆-haloalkylthio, C₁-C₆-haloalkylsulfinyl or C₁-C₆-haloalkylsulfonyl having in each case from 1 to 13 identical or different halogen atoms; C₂-C₆-haloalkenyl or C₂-C₆-haloalkenyloxy having in each case from 1 to 11 identical or different halogen atoms; C₃-C₆-cycloalkyl or C₃-C₆-cycloalkyloxy; R¹ and R² are each independently hydrogen, —C₁-C₈-alkyl, C₁-C₈-alkoxy, C₁-C₄-alkoxy-C₁-C₄-alkyl, C₁-C₄-alkylthio-C₁-C₄-alkyl or C₁-C₆-haloalkyl, R³ is hydrogen, C₁-C₈-alkyl, C₁-C₈-alkoxy, C₁-C₄-alkoxy-C₁-C₄-alkyl, C₁-C₄-alkylthio-C₁-C₄-alkyl, C₂-C₈-alkenyl, C₂-C₈-alkynyl, C₁-C₆-haloalkyl, C₂-C₆-haloalkenyl, C₂-C₆-haloalkynyl, C₃-C₆-cycloalkyl, or in each case optionally substituted phenol or phenylalkyl, wherein said carboxamide has been prepared in the presence of an acid acceptor of formula IV

in which R⁴ and R⁵ are each independently C₁-C₃-alkyl. 